Column Schedule Example: A Full Walkthrough
Here's a complete column schedule read from start to finish: a three-story commercial building with 16 columns, four marks, one splice, and every number carried through to takeoff quantities. The short version of the method: the schedule tells you what each mark is and how tall it runs; the plan tells you how many of each mark exist; length comes from subtracting base plate elevation from top-of-steel elevation. Multiply count × length × weight per foot and you have your column tonnage.
If you've never worked with one before, start with what a column schedule is and come back. This post assumes you know the schedule exists and want to see the actual arithmetic.
The Sample Column Schedule We'll Read
This is a composite of real schedules from one-off commercial jobs — a three-story office building, steel frame, slab-on-grade, with a small entry canopy. The schedule sheet is S008. Key elevations from the general notes:
- Bottom of base plate: El. 100'-0" (on 1" grout over footings)
- Level 2: El. 114'-0"
- Level 3: El. 128'-0"
- Roof top of steel: El. 141'-6"
- Column splice (where scheduled): El. 132'-0" (4'-0" above Level 3, standard practice so the splice lands above the floor beam connections)
And the schedule itself:
| Mark | Base to El. 132'-0" | El. 132'-0" to Roof | Base Plate | Anchor Bolts | Base El. | Top El. |
|---|---|---|---|---|---|---|
| C1 | W10X49 | W10X33 | PL 1"×14"×1'-2" | (4) 3/4"⌀ F1554 Gr. 36 | 100'-0" | 141'-6" |
| C2 | W12X65 | W12X65 (no splice) | PL 1 1/4"×16"×1'-4" | (4) 1"⌀ F1554 Gr. 36 | 100'-0" | 141'-6" |
| C3 | HSS8X8X3/8 | — | PL 3/4"×12"×1'-0" | (4) 5/8"⌀ F1554 Gr. 36 | 100'-0" | 112'-0" |
| SC1 | HSS8X8X1/2 | HSS8X8X1/2 (cont.) | PL 1"×14"×1'-2" | (4) 3/4"⌀ F1554 Gr. 36 | 100'-0" | 141'-6" |
Notice what the schedule does not contain: a quantity. There is no column on this table that tells you how many C1s exist. That's the single most important thing to internalize. The schedule is a legend, not a bill of materials.
Decoding Marks: C1, C2, and Grid References
Each mark is shorthand the engineer uses so the plan stays readable. On the foundation plan (S101), every column location shows a small square or wide-flange symbol at a grid intersection with the mark next to it: C1 at grid A-1, C2 at grid B-2, and so on.
On this job, the plan shows:
- C1 at grids A-1, A-5, E-1, E-5 — the four corners. Corner columns carry less load, so they get the lighter W10.
- C2 at grids B-2, B-4, C-2, C-4, D-2, D-4 — six interior columns. More tributary area, heavier section.
- C3 at four canopy footings outside gridline A — short architectural columns that stop at the canopy roof (El. 112'-0").
- SC1 at two locations flanking the stair core. The "S" prefix usually means stair or special — check the schedule rather than guessing, because on some jobs SC means "steel column" and on others it means a specific stair post detail.
So the counts are: C1 ×4, C2 ×6, C3 ×4, SC1 ×2. Sixteen columns total. Those counts came from the plan, not the schedule — the general method is covered in how to read a steel member schedule, and it applies to beam and brace schedules the same way.
Sizes and Splices: What Changes Between Levels
C1 is the interesting row. It's two different sections in one column line: W10X49 from the base to El. 132'-0", then W10X33 from the splice to the roof. For fabrication and pricing, that is two shop pieces per column location, joined by a bolted splice in the field.
This is where a common takeoff error lives. If you read "C1 = W10X49" and run it full height, you get:
- Wrong: 4 pieces × 41.5 ft × 49 lb/ft = 8,134 lb
- Right: 4 × 32.0 ft × 49 = 6,272 lb, plus 4 × 9.5 ft × 33 = 1,254 lb → 7,526 lb
That's a 608 lb overstatement on one mark — about 8% of the C1 line. Do that on a 40-column job and you're carrying a phantom ton or two into your bid. It cuts the other way too: read only the top row and you'll price W10X33 for the whole shaft and eat the difference.
C2 has no splice — one 41.5 ft stick per location. On a 41'-6" shipping length, confirm your mill and truck can handle it; most can, but a 45 ft+ column is where you start asking.
Base Plate and Anchor Bolt Columns of the Schedule
The base plate and anchor bolt columns are takeoff line items in their own right, and they're the ones most often skipped because they're "hardware."
From our schedule:
| Item | Count | Math |
|---|---|---|
| PL 1"×14"×1'-2" (C1, SC1) | 6 | 14×14×1" plate ≈ 55.5 lb each → 333 lb |
| PL 1 1/4"×16"×1'-4" (C2) | 6 | 16×16×1.25" ≈ 90.7 lb each → 544 lb |
| PL 3/4"×12"×1'-0" (C3) | 4 | 12×12×0.75" ≈ 30.6 lb each → 122 lb |
| 3/4"⌀ F1554 anchor bolts | 24 | (4 per column) × (C1×4 + SC1×2) |
| 1"⌀ F1554 anchor bolts | 24 | 4 × 6 C2 columns |
| 5/8"⌀ F1554 anchor bolts | 16 | 4 × 4 C3 columns |
Plate weight math: length (in) × width (in) × thickness (in) × 0.2836 lb/in³. A 14×14×1 plate is 14 × 14 × 1 × 0.2836 ≈ 55.6 lb.
That's roughly 1,000 lb of base plate and 64 anchor bolts that don't appear anywhere else on the drawings. If your takeoff only counts the shafts, this package is invisible. Full pricing detail — nuts, washers, embeds, grout — is in the base plate and anchor bolt takeoff guide.
From Schedule to Quantities: The Counting Math Step by Step
Now the full assembly, mark by mark. Length = top elevation − base elevation (or splice elevation, where one applies).
Step 1 — lengths:
- C1 lower: 132'-0" − 100'-0" = 32.0 ft. C1 upper: 141'-6" − 132'-0" = 9.5 ft.
- C2: 141'-6" − 100'-0" = 41.5 ft.
- C3: 112'-0" − 100'-0" = 12.0 ft.
- SC1: 41.5 ft (continuous).
Step 2 — counts from the plan: C1 ×4, C2 ×6, C3 ×4, SC1 ×2.
Step 3 — count × length × lb/ft:
| Mark | Section | Pcs | Length (ft) | lb/ft | Weight (lb) |
|---|---|---|---|---|---|
| C1 (lower) | W10X49 | 4 | 32.0 | 49 | 6,272 |
| C1 (upper) | W10X33 | 4 | 9.5 | 33 | 1,254 |
| C2 | W12X65 | 6 | 41.5 | 65 | 16,185 |
| C3 | HSS8X8X3/8 | 4 | 12.0 | 37.69 | 1,809 |
| SC1 | HSS8X8X1/2 | 2 | 41.5 | 48.85 | 4,055 |
| Columns subtotal | 20 pcs | 29,575 |
Call it 14.8 tons of column steel, plus ~1,000 lb of base plates and 64 anchor bolts. Note the piece count: 16 column locations but 20 shop pieces, because every C1 is two sticks. Your fab shop cares about pieces; your material buy cares about pounds; the schedule read has to produce both.
Two practical notes on the HSS weights: those are the catalog values (37.69 and 48.85 lb/ft), not the nominal "3/8 wall" arithmetic — HSS is produced to a design wall thickness of 0.93× nominal, so hand-calculating from the label overstates weight. And on real jobs, add your standard allowance for cap plates, stiffeners, and connection material after this base number, per your shop's history.
Cross-Checking the Schedule Against Plan Callouts
Before the number goes in the bid, run three checks. They take ten minutes and catch the expensive mistakes:
- Every plan mark exists in the schedule. Walk the plan grid by grid and tick each mark against a schedule row. A
C4on plan with no schedule row means a revision got out of sync — RFI it, don't guess. - Every schedule row appears on plan at least once. Schedules routinely carry rows for marks that were deleted in a later revision. If C3 is in the schedule but you can't find one on any plan sheet, its quantity is zero, not "probably a few."
- Elevations reconcile. Schedule top elevation should match the roof framing plan's top-of-steel. If the schedule says 141'-6" and the roof plan notes T.O.S. 140'-0" at a stepped bay, some columns are shorter than the schedule's generic row — and that's usually flagged only in a plan note.
The difference between marks resolved through a schedule and members labeled directly on plan matters for how you organize this check — that comparison is laid out in schedule marks vs. direct labels.
Why Schedules Are Where Takeoffs Most Often Go Wrong
Column schedules concentrate risk because one table row can represent anywhere from one column to forty. Miss the row-to-plan multiplication and the error scales with the building. The failure modes we see over and over:
- Counting the schedule as inventory. One row ≠ one column. C2 is one row and 16,185 lb.
- Ignoring splices and running the heavier (or lighter) section full height, like the 608 lb C1 example above.
- Skipping the hardware columns — base plates and anchor bolts are real dollars and real lead-time items.
- Software that can't connect the two sheets. A tool that finds "W12X65" as text sees it once, on S008, and counts one piece — or worse, counts the schedule text on top of the plan marks and double-counts. Why this is genuinely hard for takeoff automation is covered in why takeoff software misses schedule keys.
The fix is procedural, not heroic: read the schedule as a legend, count marks on plan, compute lengths from elevations, split at splices, and cross-check both directions. This is also a place where AI tooling has caught up — SteelFlo reads the schedule sheet, resolves each plan mark to its scheduled section, and boxes every occurrence on the plan so the count is the number of boxes you can see and verify, at 95-99% accuracy with your review as the final check.
Try It on Your Own Drawings
If you have a drawing set with a column schedule sitting in your inbox, run this walkthrough against it — schedule as legend, plan for counts, elevations for lengths. Or upload the PDF to SteelFlo and compare its schedule-resolved counts against your manual numbers: it covers 4,500+ steel sections across 6 standards, and the first 3 takeoffs are free, so a head-to-head on a real job costs you nothing but the review time.